1. Field of the Invention
The present invention relates to a method for manufacturing an SOI substrate having a so-called silicon-on-insulator (SOI) structure in which a single crystal semiconductor layer is provided on an insulating surface, and a method for manufacturing a semiconductor device having the SOI structure.
2. Description of the Related Art
Integrated circuits in which an SOI substrate called a silicon-on-insulator (hereinafter also referred to as “SOI”) having a thin single crystal semiconductor layer on an insulating surface is used instead of a silicon wafer which is manufactured by thinly slicing a single crystal semiconductor ingot have been developed. The integrated circuits using the SOI substrate have been attracting attention due to their reduced parasitic capacitance between a drain of a transistor and a substrate, which will lead to an improvement of semiconductor integrated circuits.
As a method for manufacturing an SOI substrate, a hydrogen ion implantation separation method is known (for example, see Patent Document 1: Japanese Published Patent Application No. 2000-124092). The hydrogen ion implantation separation method is a method by which hydrogen ions are implanted into a silicon wafer to form a fragile region at a predetermined depth from the surface, and a thin silicon layer is bonded to another silicon wafer using the fragile region as a cleavage plane. In addition to the heat treatment for separation of the silicon layer, it is necessary to perform heat treatment in an oxidizing atmosphere to form an oxide film on the silicon layer, remove the oxide film, and perform heat treatment at 1000° C. to 1300° C. to increase bonding strength.
On the other hand, a semiconductor device in which an insulating substrate such as high heat resistant glass is provided with a silicon layer is disclosed (for example, see Patent Document 2: Japanese Published Patent Application No. H11-163363). In this semiconductor device, a silicon layer obtained by a hydrogen ion implantation separation method is attached to a supporting substrate which is formed of a crystallized glass having a distortion point of 750° C. or higher.